CN1205025A - Ink for inkjet printer and method for producing fine color particle dispersion system for said ink - Google Patents

Abstract

The invention provides a water-based ink for an ink jet printer, which has long-term dispersion stability, stable ejection characteristics of an ink stream for an ink jet printer, and adhesion fastness of a printed image to a printing medium. The ink contains an aqueous dispersion of fine color particles obtained by coating fine pigment particles with a coating resin containing a carboxyl group (b). The surface of the fine color particles is covered with quaternary carboxyl groups in the form of quaternary ammonium salts, and the volume average diameter of the fine color particles is limited to less than 0.5 μm. The rate of increase in the volume average diameter of the fine color particles when the dry ink is redispersed in water is also limited to less than 50%.

Description

Ink-jet printer is with China ink and be used for the production method of the thin color grains dispersion system of described China ink

Invention field

The present invention relates to the production method of ink-jet printer with China ink, concrete relevant with the thin color grains dispersion system that is used for described China ink.

Prior art

Spray ink Printing has two kinds with China ink: oil China ink and water quality China ink.Because of oily China ink has unpleasant odor and toxicity, mostly adopt the water quality China ink at present.

Yet the shortcoming of conventional water quality China ink is water-fast and fade resistance can be poor, and reason is to have adopted water-soluble pigment as colorant.And the dissolving of pigment reaches molecular level, so when the duplicating person of office space used general paper to print usually, print quality extremely worsened, the diffusion of palpus shape occurs, promptly so-called ' burr '.

Usually, people tend to adopt so-called ' water quality pigment inks '.For example, this class China ink comprises the emulsion of ink and polymkeric substance, contain carbon black or pigment dyestuff in the emulsion and be scattered in the water soluble resin (as tackiness agent and dispersion medium), also comprise the decentralized China ink, include the microcapsule that parcel is scattered in colorant in the resene dispersion medium.

The used water quality pigment inks of ink-jet printer must adopt the fine as far as possible thin look grain that is scattered in water medium.For example, resin solution class water quality China ink is seen and is set forth in Japanese Patent 2512861, this patent disclosure the preparation method of the water quality China ink that is improved of a kind of performance, step comprises: (1) provides pigment and polymeric dispersant to the bispin milling apparatus, (2) pass through to grind the dispersion product that obtains pigment and polymeric dispersant, and (3) will disperse product to be scattered in the water quality mounting medium.The new case communique of Japanese patent application Hei 3-153775 introduces the water quality ink composition be used for ink-jet printer, comprises the mixture of (a) pigment and carboxylic polyacrylate resin, (b) can water-reducible organic solvent, and (c) wetting agent, and (d) water.Be thin particle though these technology can be effectively pulverized pigment, because of the increase of black viscosity due to the water volatilization in the China ink often causes printing to be interrupted, and under the worst situation, nozzle is blocked, also observes in addition, and the water resistance of printing thing is poor.

Generally, resin dispersion class water quality China ink is suitable for increasing under insensitive situation for water volatilization viscosity.In fact, the new case communique of Japanese patent application Sho 58-45272 has introduced a kind of ink composition that comprises the urethanum polymer emulsion that contains dyestuff, and, the new case communique of Japanese patent application Sho 62-95366 proposes a kind of China ink, include the dyestuff that is filled in the polymer particles intragranular, described particle derives from following approach: polymkeric substance and solvent dye are dissolved in the water-insoluble organic solvents, mix and make emulsifying mixture with the water-soluble liquid phase that contains tensio-active agent again, evaporation is subsequently desolvated, and satisfies to such an extent that contain the China ink of the dyestuff that is wrapped in the polymer particles intragranular.The new case communique of Japanese patent application Sho 62-254833 proposes a kind of method for preparing the colorant aqueous dispersions, and this method is included in the encapsulation process, and the surface tension between organic solvent and water termination is reduced to less than 10 dyne.The new case communique of Japanese patent application Hei 1-17062 proposes the recording liquid that contains the micro-capsule dyestuff of a kind of confession.Yet above colorant dispersion liquid does not have enough dispersion stabilizations, does not have gratifying ink-jet effect yet, and reason is that the tensio-active agent that adopts in the microencapsulation method has high foaming effect.

The new case communique of Japanese patent application Hei 3-240586 has proposed a kind of image forming material, and wherein, the discrete particles surface in the dispersion medium is by being covered through the expanded resin of dispersion medium.Yet because changing mutually of sol-gel easily takes place in the temperature range near room temperature, and because discrete particles instability in dispersion medium, described image forming material regular meeting causes unusual eruption.

The new case communique of Japanese patent application Hei 5-247370 has announced a kind of coloured composition that writes down elephant, includes pigment and resin, and pigment uses the resin-coated and resin that is insoluble to dispersion medium substantially to have the polymeric film wrapped pigment that polar curls.But, because above composition lacks from dispersive ability with attached to the ability on the recording paper, so must with the resin coupling as dispersion agent and fixing agent, so the practice is helpless to improve the shortcoming that jetting stability is poor, the print image water resistance is bad of China ink, even its dispersion stabilization is than containing pigment but not have the China ink of the film coating that curls also be like this when better.

In addition, the new case communique of Japanese patent application Hei 2-255875 has announced ink-jet printer water quality China ink, and it comprises pigment, water soluble resin, water-miscible organic solvent and water, wherein, " resin absorption granules of pigments " also is the granules of pigments that is fixed with water soluble resin on it by weak bond power, be scattered in the water quality medium, and in the water quality medium, be dissolved with limited amount water soluble resin (being less than 2% weight), this part resin is not adsorbed by granules of pigments.

Yet, because of aforesaid method can not provide enough linkage forces at granules of pigments and interlaminar resin, so, adopt " resin absorption granules of pigments " but the phase obtain higher dispersion stabilization.

Have again, under the situation of using " resin absorption particle ", can not long for China ink not only provides good ejection ability but also good adhesive ability is arranged on recording paper, even also be like this when not being limited in when being less than 2% (weight) by the meltage of the adsorbed water soluble resin of granules of pigments in the China ink.

The present invention aims to provide microcyst type water quality color inkjet printer with black, and it contains fine particle, has excellent dispersion stability, China ink ejection stability and micro-capsule adhesive ability on recording paper.

Disclosure of the Invention

For reaching above purpose; inventor of the present invention is through discovering in a large number; dispersion stabilization can be coated with (but not absorption) granules of pigments by resin film and obtain; and; employed will be had specific particle diameter (after this, to claim this particle to be " colored micro-capsule " sometimes by the color grains that resin film was coated with.)。No matter also find, be that liquid dispersion medium is at first removed and be dry in China ink, then with color grains before the redispersion of same dispersion medium and after, it is effective avoiding the color grains diameter to change to dispersion stabilization.

The amount of the present invention by the free resin of restriction ink-jet printer after with the dissolving of uncoated color grains in the ink composition be in a specific quantitative range, to guarantee that ink-jet printer is with black stable ejection and colored capsule grain adhering on recording medium.

Particularly, the present invention finds, does not adopt " the resin absorption granules of pigments " of planar water soluble resin in surface of pigments, but the coating resin that makes granules of pigments be had " in the water from dispersing property " is coated with, with generation " colored micro-capsule "; Like this then binding force between resin coating and granules of pigments adsorbs bigger, thereby the dispersion stabilization of pigment component in the water quality medium is improved.

In addition, the free water soluble resin is not promptly linked granules of pigments but is soluble in water, be limited in below 2% of ink composition weight of water quality ink-jet printer that contains dispersion " colored micro-capsule " as its amount, then can guarantee ink-jet printer with the stable ejection ability of China ink and granules of pigments to the raising of recording medium adhesive ability, this has also just realized target of the present invention.

The invention provides following invention:

Ink-jet printer is with black, contain colored fine grain dispersion liquid (d), dispersion liquid (d) is that carboxylic coating resin (b) coating pigment particle (a) is formed, wherein, (1) colored fine particle (d) surface contains season carboxyl (quaternary carboxyl group), and its volume mean diameter is less than 0.5 μ m, (2) " when the raw material China ink after drying gained do China ink in dispersion medium during redispersion, the rate of increase of colored fine grain average-volume diameter " less than 50%.

Ink-jet printer is characterised in that with China ink water quality medium floating coat dissolving resin amount is less than 2% of black weight.

Ink-jet printer is characterised in that with China ink the standard deviation of " doing color grains diameter frequency distribution in the black redispersion liquid " is less than 0.15.

Have, ink-jet printer is characterised in that with China ink the acid number of carboxylic coating resin (b) is between 50 to 80, and all or part of carboxyl is converted into quaternary ammonium salt under the effect of organic amine compound again.

A kind of suitable ink-jet printer production method of the colored fine particle dispersion liquid of China ink, may further comprise the steps: (1) makes following three's uniform mixing: (ⅰ) through mediating the colorize compound (V) that pigment and carboxylic coating resin (b) are made, (ⅱ) moisture and dissolve in the water quality medium of the organic solvent (e) of coating resin (b), (ⅲ) basic cpd; (2) produce colored fine grain dispersion liquid (X) by following approach: colored fine particle is scattered in the water quality medium, and colored fine particle is that season carboxyl, coated resin-coated thin granules of pigments are contained in the surface; Next, (3) remove organic solvent from dispersion liquid (X).

Aforesaid method is characterised in that and then may further comprise the steps: by adding the poor solvent to the coating resin in the colored fine particle dispersion liquid (X), the middle dissolved coating resin of colored fine particle dispersion liquid (X) is deposited on the colored fine particle; Then, from dispersion liquid (X), remove organic solvent (e).

" dry China ink in dispersion medium behind the redispersion, the rate of rise of the volume mean diameter of micro-capsule " uses following equation expression,

[(S2／S1)-1]×100

Wherein, S1 and S2 are defined as follows.The ink-jet printer of 10 μ l adds slide plate or gravelstone matter dish (cylinder plate diameter 10 to 14mm with China ink, height 10 to 15mm) (the diameter 14 to 16mm of the hole on, full depth 0.4 to 0.8mm) in, order ink-jet printer with dry 7 days of China ink in 25 ℃ in normal atmosphere, temperature, 20% relative humidity, be called the black redispersion of last drying in the hole that makes of " the redispersion fluid of dry China ink " again with 10ml water, its extension rate is 1000.The volume mean diameter of color grains is through measuring in the dry China ink of redispersion, and value is made as S2.

Simultaneously, the same ink that is used for above-mentioned steps as order is directly diluted with the pure water of 10ml, diluted 1000 times of Jimo, and in the dispersion liquid of dilution, the value of the volume mean diameter of color grains after measuring is made as S1.

Although conventional equipment can be used for measuring the volume mean diameter of color grains, the preferred Microtrac ultra-fine grain analyser of making by Leeds and Northrup company that uses.

" frequency distribution of color grains diameter in the dry black redispersion fluid " is defined as the frequency distribution mean diameter of color grains in " the redispersion liquid of dry China ink (preceding define) ", preferred volume mean diameter.

Thin color grains can be called " microcapsule granule ", " colored micro-capsule ", or " micro-capsule " in this specification sheets.

This specification sheets uses SI units system, and weight is with quality representation.

The accompanying drawing summary

Fig. 1 illustrates in the embodiment of the invention 1, the ink-jet printer frequency distribution of the volume diameter of thin color grains in the China ink.

Fig. 2 illustrates in the embodiment of the invention 1, the frequency distribution of the volume diameter of thin color grains in the dry black redispersion fluid.

Fig. 3 illustrates in the embodiment of the invention 4, the ink-jet printer frequency distribution of the volume diameter of thin color grains in the China ink.

Fig. 4 illustrates in the embodiment of the invention 4, the frequency distribution of the volume diameter of thin color grains in the dry black redispersion fluid.

Fig. 5 illustrates in the embodiment of the invention 6, the ink-jet printer frequency distribution of the volume diameter of thin color grains in the China ink.

Fig. 6 illustrates in the embodiment of the invention 6, the frequency distribution of the volume diameter of thin color grains in the dry black redispersion fluid.

Fig. 7 illustrates in the embodiment of the invention 7, the ink-jet printer frequency distribution of the volume diameter of thin color grains in the China ink.

Fig. 8 illustrates in the embodiment of the invention 7, the frequency distribution of the volume diameter of thin color grains in the dry black redispersion fluid.

Implement best mode of the present invention

Contain the printer that pigment inks is done ink-jet ink for employing, guarantee that stable the use is ten Branch necessity, asked by the obstruction of the dry caused ink nozzle of China ink so need overcome at nozzle end Topic. The tradition China ink is done decentralized medium by water miscible resin, comes the thin face of stable dispersion by absorption The material particle is easy to follow evaporation of water and the cohesion that causes thin granules of pigments. In case thin pigment Grain cohesion adds water or identical China ink may make these particles disperse hardly again, so cohesion Grain causes spray nozzle clogging. If make again dispersion after liquid medium is evaporated, dry thin face then The par whether dispersion of material particle or thin color grains reaches original China ink can be used as judgement Stop up estimating of difficulty or ease.

Might estimate color grains by measuring color grains diameter growth rate in time Cohesion performance, and particle diameter can average particulate diameter be that (50% particle is straight for median diameter Directly) characterize, or increase (for example, 90% particle diameter) sign with coarse grained diameter. This Bright discovery, average diameter be volume mean diameter and the black spray nozzle clogging of ink-jet printer particularly Be closely related.

Fitting and selecting colored fine grained is " through the granules of pigments of carboxylic coating resin (b) coating (a) ", its volume mean diameter is less than 0.5 μ m, and preferable range is 0.01 to 0.3 μ m.

The defined ink-jet printer of the present invention with the feature of China ink is " the again dispersion train of dry China ink In the body, the growth rate of the volume diameter of thin color grains (d) " less than 50%. From inkjet printing Effect, preferred ink-jet printer with the growth rate of China ink less than 40%, more preferably growth rate less than 20%.

When carrying out above two experiments, preferably from identical container, choose sample. At this In bright, open a new container, extract from container rapidly black sample, measure the body of color grains Long-pending average diameter obtains the S1 value.

Preferred S1 and S2 value are all less than 0.3 μ m.

The preferred standard deviation of " the frequency distribution diameter of color grains in the dry black again dispersion liquid " (sd) less than 0.15, be more preferably less than 0.1.

The standard deviation of the frequency distribution of S1 should be identical with above-mentioned S2.

Generally, be not limited only to the present invention, China ink contains " by the coating resin that is insoluble to decentralized medium The colored micro-capsule that coating pigment makes ", " it is also not coated resin-coated to be insoluble to decentralized medium Free granules of pigments ", " neither coating pigment also is insoluble to the coating resin in the decentralized medium The free resin particle ", " being dissolved in the coating resin in the decentralized medium ", decentralized medium and root Additives (such as drier or bleeding agent) according to needs.

For overcoming the above problems, ink-jet printer of the present invention contains colored fine grain dispersion with China ink Liquid (d), colored fine grained (d) are to be coated with through carboxylic coating resin (b) in aqueous medium Granules of pigments (a), wherein, the ink-jet printer China ink is to be defined as: (1) described colored fine grained (d) surface has the season carboxyl, and volume mean diameter is less than 0.5 μ m; (2) " dry China ink disperses again The growth rate of color grains volume mean diameter in the fluid " less than 50%.

For these conditions are worked, effectively eliminate or limit and be dissolved in free in the aqueous medium The amount of coating resin is in a scope that allows.

The amount of the coating resin of preferred dissolution is answered minimum or is limited in less than 2% of black weight.

Yet comparatively difficulty is, makes the free coating resin part of whole coating resins in the China ink Meltage regulation and control in 0.01% scope less than black quality. If free coating resin in the China ink Amount less than 0.1% of black quality, when estimating to be printed on the record-paper with this synthetic China ink, possible Because micro-capsule can not adhere to well on the record-paper surface, so that lasting with the material of this China ink printing The ability of tolerance wearing and tearing.

On the contrary, if the amount of free coating resin surpasses 2% of black quality in the China ink, when using this China ink During printing, reach the mutual bonding force of micro-capsule between micro-capsule and printing paper and all can improve, yet, when When being printed on the record-paper, such shortcoming can occur, coating resin needs very at printing paper The long time solidifies. And, also unfavorable with the ejection stability of China ink to ink-jet printer, because Compare with using water-soluble resin (such as polymeric dispersant or similar material), be accompanied by water Evaporation, coating resin is easy to cause nozzle blockage.

The amount of control coating resin is 0.01% to 2%, more preferably at the model of 0.1% to 1% (quality) In enclosing, then in the China ink between micro-capsule and printing paper and the mutual bonding force of micro-capsule, and print material Material has raising to the durability of wearing and tearing, thereby ink-jet printer obtains with the stability that China ink sprays Large increase, reason are to follow evaporation of water, and nozzle blockage has reduced.

Here, the content that is dissolved in the free coating resin in the China ink represents absolute magnitude, and it hereinafter Be called absolute content.

Among the present invention " water-soluble or water quality medium " word indication medium only moisture or water be main group Divide, and contain solvent or other required additive. In the present invention, the preferred selection as dividing Dispersion media be the Ratio of Chemical Composition of water miscible medium, to avoid making coating resin as far as possible Dissolving.

But as long as the resin film forming, just can be used as coating resin, and not only be confined to natural or close Resin, for example, styrene resin, acrylic resin, mylar and polyurethane resin. Said resin can be the resin with reversible bridging performance, and this resin is bridge at room temperature Connection, but under heat effect, be converted into non-bridging.

Just has reversible bridging performance such as ionomer resin.

But preferred coating resin is linear the connection and tool thermoplasticity, and the resin of no heat sensitivity, permanent bridging is also not preferred.

But coating resin need have very high wetting ability, in the hope of preparing stable colored microcapsule dispersion, coating resin is dissolved in the China ink in a large number.In this case, be dissolved in coating resin in the China ink in storage process because of the micro-capsule of coating resin coating and the dissolved coating resin formation bridging that is cross-linked with each other, and cause the adhesion that colored micro-capsule is mutual.In addition, in printing, owing to the agglomerative China ink of adhesion around the evaporation of nozzle place moisture and the nozzle, black viscosity is increased, the coating resin that is dissolved in the China ink can cause black improper eruption.

For example, improper eruption is relevant with the improper release or the spray nozzle clogging of China ink.

Otherwise when the wetting ability of coating resin was hanged down, the dispersion liquid of colored micro-capsule was stable inadequately.So, preferably make water quality medium floating coat resin solution minimum, in the hope of obtaining stable dispersion liquid in described water quality medium.

Can in the coating resin of non-hydrophilic or slightly water-wet originally, add tensio-active agent or dispersion agent, to obtain stable dispersion liquid.But,, should not adopt tensio-active agent or dispersion agent to regulate China ink from obtaining the good waterproof quality viewpoint of stable ink-jet release and printed material.

A kind of proper method of not using tensio-active agent or dispersion agent to regulate China ink is in adopting and resin, in this and the resinogen instinct in the water quality medium, disperse and neutralize through neutralizing agent.

Former instinct disperses in the water quality medium, in neutralizing agent and in the gained and coating resin, generally enable to be dispersed in resin in the water-bearing media use with alkali in and preparation.In the present invention, this can disperse resin under the situation of not adding tensio-active agent and dispersion agent, is called in " in the water from dispersion resin ".Preferred use is this by doing coating resin from dispersion resin in the alkali and in the water that obtains.

A typical example that contains the coating resin of acidic group is the coating resin with carboxyl (b).The colored fine particle of making through carboxylic coating resin (b) coating pigment particle (a) (d) can contact with the water quality medium by the carboxyl on coating resin surface and change into quaternary salt and be able to disperse in the water quality medium.Carboxylic coating resin can be in water soluble resin or the water from dispersion resin, this depends on that the season carboxyl accounts for the amount (by acid number definition) of whole carboxyls.

The effect of the present invention under following situation is obvious, promptly when the coating resin (b) on the pigment fine particle (d) dissolves in the water quality medium hardly, also is that coating resin is in the water state from dispersion resin.

The acid number of preferred resin is 10 to 280.

The acid number of resin is more preferably between 50 to 180.

Here, acid number by in and milligram (mg) number of 1g potassium hydroxide that resin consumes represent, represent with mgKOH/g (hereinafter, acid number unit omit).Preferred resin derives from all or part of neutralization of the acid number that makes the resin with described specific acid number.

The pH of preferred China ink is between 7.5 to 9.0.

Because the micro-capsule surface is the sufficient wetting ability of tool not, micro-capsule can not stable dispersion, so should not use acid number less than 50 resin.Also should not use acid number to surpass 180 resin, micro-capsule causes micro-capsule to take place each other to adhere to and plug nozzle because of the microencapsulation fully of expanding because the resin wetting ability is very strong.

The pH value should not be used less than 7.5 China ink, because the dispersiveness of China ink can be demoted; The pH value of China ink also is not suitable for greater than 9.0, and because of expansion makes parcel insufficient, micro-capsule adheres to and plug nozzle each other.

More preferably, adopt the coating resin of acid number 50 to 180, make its with alkali in and the back form in the water from dispersion resin, the pH value of adjusting China ink so obtains the performance of the black optimum of the present invention in 7.5 to 9.0 scope again.

Although the molecular weight to coating resin among the present invention is not particularly limited, the weight average molecular weight of preferred resin is between 1000 to 100,000.

If the weight average molecular weight of coating resin is less than 10,000, resin will be difficult to form coating, and can be because of the mutual adhesion plug nozzle between micro-capsule.

In addition, when the molecular-weight average of resin less than 10,000 o'clock, the water resistance of printed material is poor.

When adopting styrene resin or acrylic resin, the preferred resin molecular weight is between 1,000 to 100,000.

Be the acquisition favorable waterproof property, preferred resin molecular weight ranges 10,000 to 100,000, more preferably scope is 30,000 to 100,000.

The preferred coatings resin is styrene type resin or (methyl) acrylic type resin among the present invention.

As preferably, adopt multipolymer that the monomer (as vinylbenzene, vinylbenzene, substituted phenylethylene and (methyl) acrylate) of (methyl) acrylate and suitable choosing forms as resin with a certain acid number.

Have in the water of resin gained of acid number from the dispersion resin coating resin as comprising with alkali neutralization, so in the preferred water that adopts from dispersion resin be (methyl) acrylate with the monomer of suitable choosing (as vinylbenzene, vinylbenzene, substituted phenylethylene and (methyl) acrylate) acid number to the small part of the multipolymer that forms is neutralized by alkali, and the back forms.

Here, term (methyl) acrylate is that a generic term comprises vinylformic acid and methacrylic acid.

For the present invention, it is necessary that vinylformic acid and methacrylic acid are included, but more preferably, adopts the coating resin that includes the chemical structure that is made of jointly vinylformic acid and methacrylic acid.

Among the present invention, for reduce as in the water of coating resin from the dissolving of dispersion resin, preferred resin can contain acrylic acid ratio in the carboxylic monomer and reduces and the ratio of methacrylic acid is improved to obtain by making.

Like this, most preferably do in the water of coating resin and derive from following approach: the multipolymer that forms by monomer copolymerization to the small part neutralization with alkali from dispersion resin, wherein, monomer is main ingredient and is selected from such as vinylbenzene, vinylbenzene, substituted phenylethylene and (methyl) acrylate, and the amount of methacrylic acid is greater than acrylic acid amount in the multipolymer.

By adding the black pH value of neutralizing agent (alkali) control is alkalescence.

In the production method of preferred water quality ink-jet printer with China ink, alkali is used for dispersion process, and this method is introduced afterwards.

For example, alkali (claiming " basic cpd " among the present invention sometimes) comprises metal hydroxides, as sodium hydroxide, and potassium hydroxide and lithium hydroxide etc.; Basic material such as ammonia, triethylamine, morpholine etc.; Alcamines such as trolamine, diethanolamine and N methyldiethanol amine.

The preferred volatile alkali that adopts, it volatilizees under the Undec temperature of coating resin.

Need to adjust the concentration or the consumption that are used for neutral alkali, because the resin that has a higher acid value with the highly basic neutralization can increase the solution amount of coating resin in China ink.

For resin, owing to the raising of dissolving resin degree with degree of neutralization increases, so need to adjust the consumption that is used for neutral alkali according to the dissolution degree of resin in liquid medium and the particulate predetermined size in water dispersion medium with high acid value.

The solubleness of resin in water increases with the raising of degree of neutralization, yet in the redeposition process, resin does not fully deposit on color grains, is necessary the amount (degree of neutralization) of adjusting the concentration of alkali or being used for neutral alkali.

For being used for the water quality China ink of spray ink Printing, preferably make the amount minimum of soluble resin, avoiding ink-jet stability, the water resistance stable and printed material of dispersion liquid produces not right influence of phase in the storage process.To being used for the water quality China ink of spray ink Printing, optimum alkali is alcamines, as trolamine, because these hydramine are that weak base and the amount that generates described water soluble resin component are limited.

In spray ink Printing, the most suitable as the alcamines weak base of trolamine, because weak base never can be to such as spray nozzle clogging, the water resistance of the stable and printed material of dispersion liquid produces detrimental action in the storage process.

In the preparation method of more preferred water quality ink-jet printer with China ink, in the dispersion liquid treating processes, alkali is controlled at the degree that makes the resin self-emulsifying to the degree of neutralization of resin, for example is neutralized greater than acidic group in the resin of 10% (mole).

Among the present invention, alkali is defined as molar equivalent less than 100% to the degree of neutralization of resin, or is more preferably less than 60% molar equivalent.The spy adds preferably, adopts hydramine to make alkali, and the normal degree of neutralization of the acidic group of control coating resin is less than 60% (mole).

Derive from following approach from dispersion resin in the water that the present invention preferably uses: making acid number is the neutralization of 50 to 180mgKOH/g coating resin, is less than the degree that 60% coating resin acidic group equivalent is neutralized.

When obtaining colored fine particle (d), preferably with contain carboxyl, acid number be 50 to 180 coating resin (b) with its coating, wherein, all or part of carboxyl is converted into quaternary ammonium salt under the organic amine compound effect.

Any routine or known tinting material all are suitable for produces ink-jet printer each preferred method with China ink among the present invention, do not have any restriction.

For the water resistance and the fade-proof performance of the color grains through being coated with, pigment is more excellent than dyestuff.

Any routine or known pigment all can be used for the water quality ink-jet printer with the colored micro-capsule of dispersive in the China ink, do not have any restriction.To the present invention, pigment is present in the colored micro-capsule (d) with pigment fine particle (a) form.

For example, pigment comprise such as, mineral dye such as carbon black, titanium is black, titanium white, zinc sulphide and red iron oxide; And pigment dyestuff such as phthalocyanine pigment, Monoazo type and tetrazo type azo pigment, phthalocyanine and quinacridone pigment.

As hereinafter describing in detail, preferred China ink is selected from following pigment with pigment, comprises carbon black, phthalocyanine pigment, halogenated phthalocyanines pigment, quinacridone pigment, benzimidazolone pigment, perinone pigment and iso-dihydro-indole pigment.

For obtaining the color resin particle, particularly black resin particle of colour killing, adopt the carbon black or the mixture of carbon black and other auxiliary colorant, and, for obtaining the color resin particle, preferably adopt pigment dyestuff.

For forming color picture, preferably adopt coloured pigment.

For forming color picture, particularly form full-color image, minimum the use cyan (indigo plant) that needs, red-purple (red) and yellow three kinds of color combinations.A nearlyer step preferably is used in three colour cells to full-color image and closes outer four colour cells that add black again and close, and to forming color picture, also preferably adds complementary color again outside described three looks or four colour cells are closed.

From the color harmony water resistance, preferred phthalocyanine pigment is done cyan.In fact, preferred phthalocyanine pigment comprises nonmetal phthalocyanine, copper phthalocyanine, chlorinated copper phthalocyanine and other metal phthalocyanine.In these pigment, the dispersing property during from the combination of color harmony and other coloured pigment, more preferably copper phthalocyanine, the C.I. pigment Blue 15: 4 most preferably.

From the color harmony water resistance, preferred quinacridone pigment is done red-purple.In fact, dimethylquinacridone and dichloro-quinacridone can be used as quinacridone pigment.In these pigment, from the color harmony dispersing property, preferred quinacridone pigment is the C.I. pigment red 122.

From the color harmony water resistance, preferred benzimidazolone pigment is made yellow ultramarine.In fact, benzimidazolone pigment comprises C.I. pigment Yellow 12 0, C.I. Pigment Yellow 73 151, C.I. pigment yellow 154, C.I. Pigment Yellow 73 156 and C.I. pigment yellow 17 5.In these pigment, from color harmony dispersing property and fade resistance, most preferably the person is a C.I. Pigment Yellow 73 151.

From the color harmony water resistance, preferred black pigment is a carbon black, but non-ly only limits to this.

Contain phthalocyanine pigment by the China ink with carbon black respectively with at least three kinds, the color picture that is combined to form of the China ink of quinacridone pigment and benzimidazolone pigment presents splendid stable color picture, can not cause colour-change because of fading.

Especially, the preferred color picture of image stability derives from following China ink: adopt to contain the C.I. pigment Blue 15: 4 China inks as phthalocyanine pigment contain the China ink of C.I. Pigment red as quinacridone pigment, and contain the China ink that C.I. Pigment Yellow 73 151 is done benzimidazolone pigment.Further, the preferred color picture of image stability gets in the comfortable above-listed combination and adds carbon black on request.

Each pigment can use separately or use with other pigment combinations, and color picture gets the China ink of self-contained combination pigment.

Among the present invention, except that the above composition that contains four kinds of water quality China inks of preferred pigments separately respectively, the water quality China ink of the middle mass colour of mass colour between between four kinds of colors also is preferred for forming color picture on recording medium.The example of above middle shade has: halogenated phthalocyanines pigment, and imidazolone pigment, perinone pigment, iso-dihydro-indole pigment, and preferred middle shade pigment is as follows, although some China ink is an achromaticity micro-capsule decentralized China ink.(A) cyan water quality is disperseed China ink, and this China ink is included in the micro-capsule in the water quality medium, and micro-capsule is to make through the halogenated phthalocyanines pigment fine particle that coating resin is coated with.(B) tangerine look water quality is disperseed China ink, and this China ink comprises the micro-capsule in the water quality medium, and micro-capsule is the imidazolone pigment through the coating resin coating, perinone pigment, and the fine particle of iso-dihydro-indole pigment makes.

In (A) type with (B) in the water quality medium of type China ink, after each water quality China ink combination, the amount that preferably will be dissolved in the free coating resin in the dispersion medium is restricted between between 0.01% to 2% (quality).

Although the content to granules of pigments in the China ink does not have concrete standard, as desire to make China ink to reach target of the present invention, the content of preferably adjusting pigment is between between 0.5% to 20% (quality).

As preferably, the surface of color grains is at least partly or entirely covered by coating resin, and the ratio of preferred coatings resin quality and pigment mass is 0.5% to 2%, but this ratio fibrous root decides according to the specific surface area of granules of pigments and the thickness of institute's covering resin.

Among the present invention, because of granules of pigments almost completely coated resin cover, and do not have free resin in the China ink, pretend to approximate, colored micro-capsule includes and is used for the nearly all pigment of China ink in the China ink.

Write down with China ink among the preparation method (detailed back) who uses the water quality China ink at a kind of ink-jet printer for preparing, adopt the pigment and coating resin of equal in quality proportioning, can obtain preferred result with certain acid number.The equal in quality proportioning is meant the identical in quality of pigment and coating resin, or the quality of pigment be the coating resin quality ± 15% scope in.

If desired, can in China ink, add and do not make coating resin dissolving or difficulty make coating resin dissolved organic solvent.For example, the such organic solvent that uses in the China ink comprises siccative or permeate agent.

Siccative is in order to prevent the drying of nozzle place China ink.

Generally, siccative is the boiling point reagent high than water.Any routine or known siccative all are available, comprising polyvalent alcohol, and such as ethylene glycol, propylene glycol, Diethylene Glycol, dipropylene glycol, polyoxyethylene glycol, polypropylene glycol, and glycerol.

When using glycerol, stop the drying of China ink the most effective.

Specifically, glycerol has been strengthened the dispersion stabilization of micro-capsule, because glycerol is combined closely with strong hydrogen bonding and coating resin, simultaneously, if free coating resin is arranged, glycerol is also used strong hydrogen bonding and combined with it, so just prevented the drying of nozzle place China ink.

Permeate agent is in order to the infiltration of adjustment recording medium China and Mexico and the spot diameter on the controlling recording medium.The example of permeate agent comprises inferior alcohols, such as ethanol, Virahol; The rare oxide compound of second is to the adducts of alkyl alcohol, as glycol hexyl ether, and the Diethylene Glycol butyl ether; Third rare oxide compound is to the adduct of alkyl alcohol, as propylene glycol propyl ether.

The strong perviousness of organic solvent can be destroyed micro-capsule usually and reduce the stability of China ink.May keep the stability of micro-capsule by adding an amount of at least a compound, these compounds are selected from: (k) by the adducts of 1mol third rare oxide compound to monohydroxy-alcohol, (l) by the addition polymer of 10 to 40mol third rare oxide compounds, (m) by the adducts of the rare oxide compound of 1mol second to the monohydroxy-alcohol that contains 4 to 8 carbon atoms to the monohydroxy-alcohol that contains 11 to 6 carbon atoms.The mixture of two kinds of compounds selecting in preferably using above-mentioned three groups.

Generally, in China ink, add the diffusion that a kind of emulsified dispersed liquid foam preventer that contains siloxanes can prevent recording medium, prevent foaming, guarantee the stable ejection of China ink.In the present invention, adopt above-mentioned three groups of compounds more effective, but not contain the emulsification dispersion foam preventer of siloxanes.

(k) 1mol third rare oxide compound to monohydroxy-alcohol example be the single adducts of third rare oxide compound (1mol) to propyl alcohol.

(l) 10 to 40mol third rare oxide compounds are the single addition polymer of third rare oxide compound (17.7mol) to butanols to the monomeric example of addition polymer of the monohydroxy-alcohol that contains 11 to 6 carbon atoms.

(m) the rare oxide compound of second (1mol) is the rare oxide compound of second (1mol) to the adduct monomer of butanols and second rare (1mol) the oxide compound single adducts to hexanol to the example of single adducts of monohydroxy-alcohol.

Preferably with product (k), (l) and (m) add in the China ink with the foaminess that reduces China ink and prevent being separated of China ink surface, therefore, though to the amount that adds without limits, the amount that adds is preferably in 0.01% to 10% (quality) scope.

When organic solvent is when the siccative, the amount of its adding preferably in 1% to 80% (quality) scope, and when organic solvent be when being used as permeate agent, preferably in 0.01 to 10% (quality) scope.

Because with the type of resin or the difference of organic solvent concentration, organic solvent dissolves the coating of granules of pigments sometimes, cause in the China ink the free dissolved resin greater than 2% (quality) and have influence on the China ink stable ejection, so must consider the type of solvent and the pH value of China ink, generally must adjust the concentration of organic solvent so that the dissolved free resin is no more than 2% (quality) in China ink, more preferably no more than 1%.

For the dispersion medium of product China ink, the medium that can cause coating resin dissolved organic solvent is formed, do not contained substantially to preferred the use mainly by water.If the organic solvent (e) of coating resin is dissolved in essential use in China ink, preferably reduce the concentration of organic solvent, make it to dissolve the resin (b) that is contained in the quaternary salt that forms on thin color grains (d) surface.

The invention provides have high print performance, waterproof and fade resistance can the water quality China ink, also provide have high dispersion stability, ejection is stable, the water quality China ink that do not block inkjet nozzle.

When the content of the solid constituent outside the removing coating resin in a kind of China ink hangs down, the amount that is dissolved in the free resin of black floating coat resin can be measured by a kind of method, in the method, at first make the micro-capsule precipitation by centrifugation, the thorough drying supernatant liquor is measured the amount as the free resin of non-volatilization component then.On the other hand, if have a large amount of solid ingredients and high boiling organic solvent in the China ink, measuring method is carried out as follows: the thorough drying throw out, different based on the decomposition temperature of resin and pigment, utilize the ratio of hot analysis to measure resin and pigment, make the amount of free resin by the minimizing of initial ratio between coating resin and the granules of pigments.Only be made up of colored micro-capsule when solid dispersion, do not comprise no resin-coated free color grains, when also not comprising " only for coating resin but not the particle of granules of pigments ", the measurement of a kind of method in back is comparatively accurately.When containing drying retarder or permeate agent in the China ink,, can measure more accurately by under the Undec temperature of coating resin, removing these additives.

Hereinafter, described a kind of preferred method that applies granules of pigments when preparation water quality ink-jet printer is used the colored microcapsule dispersion of China ink with coating resin, wherein coating resin has certain acid number.According to this coating method, can obtain a kind of preferred China ink that contains colored micro-capsule, but not contain " not by resin-coated free granules of pigments ", also do not contain even " only for coating resin but not the particle of granules of pigments " of minute quantity.

Method hereinafter described is convenient to a kind of preparation of preferred China ink, this China ink only contains colored micro-capsule, but do not contain " not by resin-coated free granules of pigments ", also do not contain even " only for coating resin but not the particle of granules of pigments " of minute quantity, and, this method than phase transfer method more preferably, the latter is by after adding the water quality medium, make the dispersion liquid generation phase transition emulsification of thin color grains in the organic solvent, thereby remove organic solvent.Described method comprises following process.

[1] coloring resin process: colored reagent is scattered in the coating resin with certain acid number, gets the solid colorful compound;

[2] suspension process: will be water at least at first, the organic solvent of solubilized coating resin, alkali mixes mutually with the compound that said process obtains, and by disperseing, must contain the suspended substance of colored reagent and the coating resin of solubilised state again.

[3] redeposition process: make the resin Composition that is dissolved in the suspension that the suspension process obtains be deposited in colored reagent surface.During enforcement, this method is followed following steps＜1〉and is carried out to＜5 〉.

＜1〉by being dispersed in, colored reagent obtains a solid colorful compound (kneading process) in the coating resin with certain acid number.

This step makes colored reagent reach homodisperse in solution or hot melt figure's coating resin by turnery, stirring mill or ball milling method, obtains solid then and mediates product (solid colorful compound).

Thinner if desired dispersion, the preferred high relatively dispersing method of shearing force in method commonly used, the i.e. dispersing method that grinds with the bispin of high shear force.

＜2〉pass through water, the organic solvent of solubilized coating resin and solid colorful compound mix mutually, obtain the suspension of colored reagent, wherein comprise the coating resin (suspension process) that is partly dissolved attitude at least.

The organic solvent that is used for dissolving coating resin can be chosen from the good solvent of described resin.The example of the solvent of dissolving coating resin comprises ketones solvent such as acetone, dimethyl ketone and methyl ethyl ketone; Alcoholic solvent such as methyl alcohol, ethanol and Virahol; Chloride-based solvent such as trichloromethane and vinyl chloride; Aromatic solvent such as benzene, toluene etc.; Esters solvent such as acetyl ethyl ester; Gylcol ether such as methyl glycol, glycol dimethyl ether; And acid amides.

The dispersion medium of using among the present invention mainly is a water, and it is a kind of poor solvent to coating resin, and water as ink-jet printer with the China ink dispersion medium the time, the purity of water is preferably greater than deionized water.

In said process of the present invention, preferably make the homogeneous mixture of water and organic solvent, if do not obtain enough uniformity coefficient, need, preferably add tensio-active agent so that its machinery emulsification is the O/W emulsion, perhaps add secondary solvent.

When the organic solvent that only adopts soluble resin, water and alkali are difficult to obtain homodisperse liquid, can in above-mentioned dispersion liquid, add can not dissolving resin hydrophilic organic solvent keep emulsive stability as solubility promoter.No matter be to organic solvent or to solubility promoter, only with a kind of, or two or more mixtures all can.

If coating resin is (methyl) acrylic acid and is selected from that benzene second is rare, substituted benzene second is rare, at least a monomeric multipolymer of (methyl) acrylic acid ester, make solubility promoter then preferably with ketone such as the methylethylketone organic solvent of deciding, and with alcohols such as Virahol.

Though the ratio of water and organic solvent without limits, the ratio of preferably water/organic solvent is in 10/1 to 1/1 scope.

According to this process, have coating resin self-emulsifying under the effect of organic solvent, alkali of certain acid number, and be that a part of resin gets off from solid colorful compound surface dissolution at least, so obtain the dispersion liquid of colored reagent.

After coating resin is dissolved in the liquid medium fully, just come out in the surface of colored reagent.Yet, when resin is in the self-emulsifying state, can suppose that the colored reagent of at least a portion is covered with by resin coating.

In this process, the coating resin on solid colorful compound surface has certain acid number, and all of this acid number or a part are neutralized by alkali gradually, and the solid colorful compound is also by the solid-state suspended state that becomes.

Any routine or technique known all can be used for stirring to obtain suspension, select for use single shaft propeller type to mix paddle or any type of stirring blade or agitator as required, all may obtain suspension.

When color grains through the stirring in＜2〉step can not be ground into fine particle because of lacking shearing force the time, or when colored reagent trends towards mutual conglomeration, preferably impose high shear force and make it the suspension that is ground into fine particle and obtains high dispersion stability.For this reason, for example, preferably use the dispersing apparatus such as the high-pressure homogenizer of ad hoc type or do not have the pearl dispersing apparatus such as Microfluidizer or Nanomizer (board name), the latter preferably uses when preventing the condensing again of colored reagent.

For example, when comprising colored reagent particulate suspension be ground into relatively little particle diameter in dispersion process, redeposition process＜3〉just should be carried out after dispersion process immediately.On the other hand, when the solid colorful compound contains organic pigment as colored reagent, or when the solid colorful compound contains mineral dye such as carbon black, preferably in dispersion process＜2〉with comprise another again between the deposition process＜3〉and make suspension expose under high shear process, in order to increase the stability of previous compound suspension, again the colored reagent particle in the suspension of a back compound is converted into fine particle.

＜3〉make the coating resin that is dissolved in the colored reagent suspension be deposited on colored reagent particle surface (redeposition process).

In this step, obtain micro-capsule by making the coating resin component be deposited on surface of pigments.

This step makes the coating resin that is dissolved in the pigment suspension be deposited on surface of pigments.Term " redeposition " is not the color grains that refers to precipitation and isolate half cryptomere from liquid medium, is the surface that is adsorbed on colored reagent at this coating resin that is dissolved in the suspension.Therefore, resulting in this step not merely is the mixture of solid ingredient and liquid ingredient, but color resin particulate steady suspension, and wherein colored reagent particle surface is applied and be dispersed in the liquid medium of suspension because of absorption dissolved resin.

When the suspension of colored reagent was the suspension of pigment, this step was exactly to make to be dissolved in the resin precipitated in the suspension or to be deposited on surface of pigments.Term " deposition " again is not to instigate in the half cryptomere particle of adsorption pigment or dissolving resin to separate.Therefore, resultingly in this step just do not contain the independently isolating material of solid and liquid, but obtain steady suspension, wherein, the surface absorbed dissolving resin in the liquid medium of colored reagent particles dispersed at suspension of coating.

That is to say that the resin after the dissolving is in the deposition on color grains surface or be deposited in the suspension and carry out, at that time, in free colored reagent of color grains surface coated and/or the water from dispersion resin; Colored reagent particle from dispersion resin in free colored reagent of surface coated and/or the water then is dispersed in the water base dispersion medium.

Surface coverage can be undertaken by reducing in the water the solubleness of dissolved resin Composition from the deposition of the resin of the color grains surface dissolution of dispersion resin or precipitation in free colored reagent and/or the water.

Generally, reduce that the method for the solubleness of dissolving resin component comprises, add the poor solvent of necessary amount, or from the suspension system, remove the chemical composition of the soluble resin component of necessary amount to the water quality medium that contains dissolving resin.Therefore, dissolving resin is preferential to be arrived free colored reagent and/or has covered in the water from the colored reagent particulate surface of dispersion resin, and dissolving resin is with intensive attitude accumulation and be deposited on this surface.

In the suspension process, dissolving resin is easily undertaken by following each step in the deposition of colored reagent particle surface, 1. in the suspension of the colored reagent that contains coating resin (having a part at least is dissolved state), add water quality medium, or 2. from the suspension of colored reagent, remove organic solvent as the poor solvent of described resin.

Yet,, more preferably use the method that adds as the water quality medium of poor solvent from preventing particle agglomerative viewpoint.During deposition, follow slow stirring, drip the water quality medium suspension, like this then preventing that the pigment agglomerative from having guaranteed the deposition of resin in the color grains surface simultaneously.

Be to guarantee the deposition of resin, deposition preferably 1., carry out after 2. in step: 1. in the pigment suspension of the coating resin that contains solubilised state or dispersed, add water quality medium, and 2. remove organic solvent in the pigment suspension then as poor solvent.

Moreover, for preventing the drying of dispersion liquid, preferably in dispersion liquid ahead of time or behind deposition step, add siccative.

When the dispersion liquid that will herein obtain was used as China ink, the suspension process was handled so that it uses China ink also to guarantee stable ejection of China ink as ink-jet printer.

For dispersion liquid being used as the recording medium in the ink-vapor recording, average particulate diameter is reduced to submicron particles diameter (less than 1 μ m).

The color resin particulate aqueous dispersions system that contains diameter and be submicron adopts the method for preparing color resin particulate aqueous dispersions to obtain, aspect the ejection characteristic of China ink, this dispersion liquid shows that it is suitable to the characteristic of water quality ink-jet printer with China ink at the stability of dispersion liquid and ink-jet printer.As hereinafter being described further, when this prepares the method for color resin particulate aqueous dispersions when application,, obtain to have the highly stable dispersion liquid of good dispersion stabilization and the China ink of excellent property by in suspension process (2), adding siccative toward suspension.

In aforesaid way, the color resin particle of preferred tool particular particle size derives from above-mentioned＜1〉mixing process, and＜2〉dispersion process and＜3〉are deposition process again, and is general, average particulate diameter be controlled at greater than 0.01 and scope less than 1 μ m in.

＜4〉removing and/or concentration process (desolventizing process) of the low boiling point organic solvent in the deposition process gained microcapsule dispersion again.

Though can directly use at the color resin particle suspension liquid that deposition process again obtains, but as preferred, carry out solvent removal, with the dispersion stabilization that improves storage period and prevent fire or pollution, reason is that the color resin particle with the coexistence of organic solvent is in swollen state.

When the needs continuous production, the organic solvent of removing in this process can not burn and recycling in closed system.

The color resin particulate aqeous suspension that obtains is a kind of aqueous dispersions of the colored micro-capsule of being made by resin and pigment raw material from＜1〉to＜4〉step, this suspension contains any three kinds of following materials hardly: " free granules of pigments ", " the only particle that is formed by coating resin " and " solubilised state coating resin ".Yet, be unusual difficulty owing to remove the dissolving resin component, so substantially, the total mass content of dissolving resin component in dispersion liquid matter is greater than 0.01% level.

Like this, the dispersion liquid that obtains almost is made up of colored micro-capsule and dispersion medium, and colored micro-capsule is the pigment with the coating resin coating.The content of colored micro-capsule is set in 10% to 40% the scope of micro-capsule and dispersion medium and additive (as adding) total amount.

Ink-jet printer among the present invention contains thin color grains with China ink, the latter be coated with coating resin and and be dispersed in the granules of pigments (a) of dispersion medium, wherein, (1) surface coverage of thin color grains (d) resin season carboxyl and the mean diameter of thin color grains less than 0.5 μ m, (2) " do increment rate of the volume mean diameter of thin color grains in the black redispersion liquid " less than 50%.The preferred black method of this ink-jet printer of production that adopts hereinafter described, its step comprises:

(1) make following material uniform mixing: (ⅰ) by mediating the colorize compound (V) that pigment obtains, (ⅱ) by water with can dissolve the water quality medium (W) that the solvent (e) of coating resin (b) is formed, and (ⅲ) a kind of alkali cpd;

(2) be coated with thin granules of pigments (a) with carboxylic coating resin (b), and the thin color grains of the thin color grains by carboxyl will be arranged is distributed to and obtains dispersion liquid (X) in the water quality medium on coating surface; Then,

(3) by in the dispersion liquid of thin color grains, adding poor solvent, make the coating resin (b) that is dissolved in the water quality medium be deposited on the dispersion medium surface of thin color grains, from dispersion liquid, remove organic solvent then coating resin.

In dispersion liquid (X), do not have when containing the dissolving coating resin of season carboxyl (that is, the salt structure), or, need not add the poor solvent of coating resin, just remove organic solvent (e) and get final product when the thin color grains (d) in the dispersion liquid when enough stablizing.

＜5〉black forming process

Only moisture or almost have only the dispersion liquid of the thin color grains of submicron-scale of water to can be used as ink.Yet, preferably the performance of dispersion liquid is adjusted, to guarantee dispersive stability and discharge performance.

Generally, as mentioned below, when adjusting, adopt the strainer that prodefined opening is arranged to filter dispersion liquid, with the ink that obtains providing with dispersion, contain among the latter less than opening diameter, be dispersed in the particle in the liquid medium.

For example, adjustment comprises adding siccative and permeate agent, adjusts concentration and viscosity, and if desired, add the pH value and adjust agent, in order to the tensio-active agent of control dispersion, foaming and the infiltration in paper, sanitas, sequestrant, softening agent, antioxidant and UV light absorber etc.

Yet the compound that is necessary to select the following feature of tool for use is as additive, and this compound does not dissolve the resin coating on the colored micro-capsule, even selected additive solubilized coating, add-on also should be limited to and not make coating dissolved level substantially.

When recording medium is when being made by non-permeate substance such as glass or metallic membrane, outside the removing coating resin, also can add a certain amount of other water soluble resin not influence its ejection characteristic.

In order to prevent that nozzle from being blocked by coarse particles, after＜4〉the desolventizing process in step, with centrifugation or filtration, or after＜5〉the black adjustment process in step, use and filter, to remove coarse particles.

The colored micro-capsule water quality of aqueous dispersion type of the present invention China ink can be used for any routine or the ink-jet printer of knowing altogether such as Piezo type or portable printer.With the exception of this, China ink of the present invention also is used in paper, and resin-coated, spray ink Printing dedicated paper, glass, metal, imaging on pottery and the porcelain.

The colored micro-capsule water quality of aqueous dispersion type of the present invention China ink all is being outstanding aspect transparency and the colour film developing, except that as the spray ink Printing, also can be used as common ink, coating and color filtration.

Hereinafter described be the different black examples that obtain with the present invention.

1, contains the thin color resin particulate aqueous dispersion type water quality China ink of particle diameter less than nozzle diameter, wherein, this China ink can be realized stable ejection and stopped nozzles not, and all belongs to goodly aspect the water resistance of dispersion stabilization when storing and printing thing, and this China ink can obtain by following process.

[1] coloring resin process: distribution of at least one pigment in having the coating resin of certain acid number, to obtain the solid colorful compound.

[2] obtain the suspension process of pigment suspension:, adjust coating resin again and make it oneself disperses and a part of coating resin is dissolved in the suspension in water at first with the solid colorful compound be that the organic solvent of water, dissolving coating resin, the alkali that can reduce the coating resin amount mix at least.

[3] the redeposition process of minimizing water soluble resin group component: add water quality medium, in above-mentioned suspension, remove organic solvent subsequently, and make the dissolving resin component in the said process gained suspension be deposited on surface of pigments as poor solvent.

2, contain the colored micro-capsule ink-jet printer of aqueous dispersion type of colored micro-capsule with black, colored micro-capsule is by with being self-dispersed coating resin coating pigment acquisition in the water in essence, wherein, be dissolved in the percentage composition of the coating resin in the China ink in 0.1 to 2% (quality) scope.

3, contain the colored micro-capsule ink-jet printer of aqueous dispersion type of colored micro-capsule with black, colored micro-capsule is by with being self-dispersed coating resin coating pigment acquisition in the water in essence, wherein, be dissolved in the percentage composition of the coating resin in the China ink in 0.1 to 1% (quality) scope.

4, contain the colored micro-capsule ink-jet printer of aqueous dispersion type of colored micro-capsule with black, colored micro-capsule is by with being self-dispersed coating resin coating pigment acquisition in the water in essence, wherein, be dissolved in the percentage composition of the coating resin in the China ink in 0.01 to 2% (quality) scope.

5, contain the colored micro-capsule ink-jet printer of aqueous dispersion type of colored micro-capsule with black, colored micro-capsule is by with being self-dispersed coating resin coating pigment acquisition in the water in essence, wherein, the absolute percentage composition of the coating resin in the China ink is in 0.1 to 1% (quality) scope.

6, above-mentioned 1,2,3 and 4 described China inks, the pH value of its China and Mexico is in 7.5 to 9.0 scope.

7, above-mentioned 1,2,3,4 and 5 described China inks, wherein having the weight-average molecular weight that the coating resin from dispersing characteristic has in water is 30,000 to 100,000.

8, the China ink described in above-mentioned 2,3,4,5,6 and 7, wherein micro-capsule obtains by finishing following process in proper order.

[1] coloring resin process: distribution of at least one pigment in having the coating resin of certain acid number, to obtain the solid colorful compound.

[2] obtain the suspension process of pigment suspension:, adjust coating resin again and make it oneself disperses and a part of coating resin is dissolved in the suspension in water at first with the solid colorful compound be that the organic solvent of water, dissolving coating resin, the alkali that can reduce the coating resin amount mix at least.

[3] redeposition process: make the dissolving resin component in the said process gained pigment suspension be deposited on surface of pigments.

9, the China ink described in above-mentioned 2,3,4,5,6 and 7, wherein colored micro-capsule is finished following process by order and is obtained.

[1] coloring resin process: distribution of at least one pigment in having the coating resin of certain acid number, to obtain the solid colorful compound.

[2] obtain the suspension process of pigment suspension:, adjust coating resin again and make it oneself disperses and a part of coating resin is dissolved in the suspension in water at first with the solid colorful compound be that the organic solvent of water, dissolving coating resin, the alkali that can reduce the coating resin amount mix at least.

[3] redeposition process:, make the dissolving resin component in the said process gained pigment suspension be deposited on surface of pigments by reducing the solubleness of resin Composition in the water quality medium.

10, the China ink described in above-mentioned 2,3,4,5,6,7, wherein colored micro-capsule is finished following process by order and is obtained.

＜1〉coloring resin process: distribution of at least one pigment in having the coating resin of certain acid number, to obtain the solid colorful compound.

＜2〉obtain the suspension process of pigment suspension:, adjust coating resin again and make it oneself disperses and a part of coating resin is dissolved in the suspension in water at first with the solid colorful compound be that the organic solvent of water, dissolving coating resin, the alkali that can reduce the coating resin amount mix at least.

＜3〉redeposition process: add water quality medium, in above-mentioned suspension, remove organic solvent subsequently, and make the dissolving resin component in the said process gained suspension be deposited on surface of pigments as poor solvent.

11, the China ink described in above-mentioned 2,3,4,5,6,7, wherein colored micro-capsule is finished following process by order and is obtained.

＜1〉coloring resin process: distribution of at least one pigment in having the coating resin of certain acid number, to obtain the solid colorful compound.

＜2〉obtain the suspension process of pigment suspension:, adjust coating resin again and make it oneself disperses and a part of coating resin is dissolved in the suspension in water at first with the solid colorful compound be that the organic solvent of water, dissolving coating resin, the alkali that can reduce the coating resin amount mix at least.

＜3〉the redeposition process of minimizing water soluble resin group component: add water quality medium as poor solvent, in above-mentioned suspension, remove organic solvent subsequently, and make the dissolving resin component in the said process gained suspension be deposited on surface of pigments by the solubleness that reduces resin Composition in the water quality medium.

12, the China ink described in above-mentioned 1,2,3,4,5,6,7,8,9,10 and 11, wherein pigment is identical with the consumption of the coating resin with certain acid number, or the amount of used pigment between resin demand ± 15% scope in.

13, the China ink described in above-mentioned 2,3,4,5,6 and 7, wherein acid number 50 to 180mgKOH/g, in water, have coating resin from dispersing characteristic to be neutralized the back to use at its acid number not as good as 60%.

14, the China ink described in above-mentioned 1,8,9,10 and 11, wherein acid number 50 to 180mgKOH/g, in water, have coating resin from dispersing characteristic to be neutralized the back to use at its acid number not as good as 60%.

15, the China ink of the following feature of tool, thin color grains (d) wherein is coated with thin granules of pigments (a) by carboxylic coating resin (b) and forms and be dispersed in the water quality medium, wherein, (1) contain the season carboxyl on described thin color grains (d) surface, and (2) " increment rate of the volume mean diameter of thin color grains in the redispersion liquid " is less than 50%.

16, the China ink described in above-mentioned 15, the amount that wherein is dissolved in the coating resin in the water quality medium is less than 2% of black weight.

17, the China ink described in above-mentioned 15 and 16, wherein the standard deviation of " doing the volume mean diameter frequency distribution of thin color grains in the black redispersion liquid " is less than 0.15.

18, the China ink described in above-mentioned 15,16 and 17, the acid number of wherein said coating resin is in 50 to 180 scope, and all or part of acid number is converted into quaternary ammonium salt by organic amine.

19, a kind of method for preparing China ink contains the following step:

(1) makes following material uniform mixing: (ⅰ) the colorize compound (V) that obtains by the coating resin (b) of mediating pigment and band carboxyl, (ⅱ) by water with can dissolve the water quality medium (W) that the solvent (e) of coating resin (b) is formed, and (ⅲ) a kind of alkali cpd;

(2) prepare the dispersion liquid (X) of thin color grains (d) in described water quality medium (W), wherein use carboxylic coating resin (b) to be coated with thin granules of pigments (a) making thin color grains (d), and comprise the season carboxyl at coatingsurface; Then,

(3) from dispersion liquid (X), remove organic solvent.

20, the method described in above-mentioned 19, and then comprise settling step, promptly by adding the poor solvent of coating resin (b), make the coating resin (b) in the water quality medium that dissolves thin color grains dispersion liquid (X) be deposited in thin color grains (d) surface, from dispersion liquid (X), remove organic solvent (e) then.

21, the China ink described in above-mentioned 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19 and 20 wherein should adopt the single adducts of 1 mole of third rare oxide compound to monohydroxy-alcohol by China ink.

22, the China ink described in above-mentioned 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20 and 21 wherein should China ink adopts the single adducts of 1 mole of third rare oxide compound to the monohydroxy-alcohol that contains 1 to 6 carbon atom.

23, the China ink described in above-mentioned 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21 and 22 wherein should China ink adopts the single adducts of 1 mole of third rare oxide compound to the monohydroxy-alcohol that contains 4 to 8 carbon atoms.

24, the China ink described in above-mentioned 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22 and 23, wherein this China ink is selected at least two kinds of following compounds for use: 1 mole of third rare oxide compound is to single adducts of monohydroxy-alcohol, 1 mole of third rare oxide compound be to single adducts of the monohydroxy-alcohol that contains 1 to 6 carbon atom, and 1 mole of third rare oxide compound is to single adducts of the monohydroxy-alcohol that contains 4 to 8 carbon atoms.

25, the China ink described in above-mentioned 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23 and 24, wherein pigment is selected from: carbon black, phthalocyanine pigment, halogenated phthalocyanines pigment, quinacridone pigment, benzimidazolone pigment, penorine pigment, iso-dihydro-indole pigment.

26, a kind of method for preparing above-mentioned 19,20,21,22,23 and 24 described China inks also comprises in this method and remove the coarse grained step that diameter surpasses 0.5 μ m from suspension.

Hereinafter the preparation method with ink for inkjet recording is an example, and the preferred embodiments of the invention are described.This method comprises the following step:

(1) by disperse to form by the multipolymer of coating vinylbenzene and (methyl) acrylic acid ester, weight average molecular weight range 10,000 to 100,000 and acid number obtain the solid colorful compound at the resin of 50 to 180 (they are basic with the carboxyl);

(2) adopt the organic solvent of water and lower boiling, solubilized coating resin to prepare the solution of mainly forming by water, hydramine and glycerol additive, wherein organic solvent is formed by the main solvent methyl ethyl ketone and as the Virahol (secondary solvent of methyl ethyl ketone and water-soluble) of solubility promoter, hydramine reaches 60% mole of acid number degree of neutralization as alkali, usefulness so that acid neutralizes, the glycerol additive is as siccative, thereafter, the solid colorful compound that above-mentioned (1) step is obtained mixes and stirs the suspension of acquisition pigment with this solution.In addition,, preferably use dispersing apparatus such as Nanomizer (board name) under high shear to stir, to obtain more stable dispersion liquid for preventing to condense again.

(3) drip glycerol solution down by stirring, obtain only to contain mean diameter greater than 0.01, less than the aqueous dispersions of the color resin particle (colored micro-capsule) of 1 μ m.The amount that is dissolved in the resin in the dispersion liquid is less than 0.1 to 1.0% (quality).

(4) from the color resin particulate aqueous dispersions that obtains, remove methyl ethyl ketone and Virahol, obtain the alkali lye of China ink.

(5), obtain to contain the above-mentioned colored micro-capsule 0.5% to 20% (quality), the pH value that are converted into pigment and be 7.5 to 11 ink-jet printer with black by adding after China ink adjusts agent and adjust the concentration and performance of black alkali.The content that is dissolved in the coating resin in the China ink is adjusted in 0.1% to 1.0% (quality) scope.

Hereinafter will utilize embodiment and Comparative Examples for a more detailed description to the present invention.The unit that uses in following embodiment and the Comparative Examples " part " refers to " mass parts ".

The diameter of thin color grains (colored micro-capsule) is to measure with the Microtrac ultra-fine grain analyser that Reeds and Northrup Co. company produces.When measuring the volume mean diameter of above-mentioned thin color grains, use and before this specification sheets, use slide plate with holes.Embodiment 1

Get 20 parts of bispins and mediate product, this product includes 20 parts of carbon blacks and 20 parts of styrene-propene acid-methacrylic resin (styrene/acrylic/methacrylic acid=77/10/13; Molecular weight=50,000; Acid number=160), add subsequently in the mixing solutions of forming by 210 parts of water, 35 parts of glycerol, 8 parts of trolamines, 90 parts of methyl ethyl ketones and 40 parts of Virahols, at room temperature stir the suspension that obtained colored reagent in 3 hours.

Then under agitation, with the speed 30 parts of glycerol of dropping of 5ml/min and the mixture of 210 parts of water, obtain the resin dispersion liquid of black.From then on remove methyl ethyl ketone and Virahol in the capsule solution with rotatory evaporator, obtain black resin particulate aqueous dispersions at last.Obtain ink for inkjet recording after filtering this aqueous dispersions with the strainer in 1 μ m hole.

The average particulate diameter of the micro-capsule in the water quality China ink that obtains like this is 0.09 μ m, this China ink demonstrates permanent stability and is non-caked, ink-jet printer with the Piezo type is stable with the symbol that black printer was write down, and demonstrate clearly black by the printing thing that this China ink obtains and do not have diffusion, water resistance is also good.Micro-capsule in the water quality China ink uses super centrifuge separator at acceleration 9.8km/s ²The following precipitation 3 hours of centrifugal condition, with this throw out at 150 ℃ of dry down pigment that obtained being coated with coating resin in 140 hours.Can record the resin Composition that is dissolved in the China ink with the ratio of hot analysis to measure resin and pigment is 0.3% (quality).This China ink demonstrates the stably stored characteristic and Achromatic color particulate bonding, and it all is being outstanding aspect waterproof and the light stability that the printing thing that the present invention obtains was at room temperature preserved after 1 year.The comparative example 1

Composition that will be identical with embodiment 1 is except mediating carrying out bispin the methyl ethyl ketone (a kind of fine solvent that dissolves coating resin), yet, agitate compounds is not dissolved in the water quality medium identical with embodiment 1, just obtains the dispersion liquid for the preparation China ink.Embodiment 2 (first example of red-purple China ink)

Get 40 parts of bispins and mediate product, this product contains 40 parts of quinacridones and 40 parts of styrene-propene acid-methacrylic resin (styrene/acrylic/methacrylic acid=77/10/13; Molecular weight=50,000; Acid number=160), add subsequently in the mixing solutions of forming by 250 parts of water, 22 parts of glycerol, 8 parts of trolamines (being equivalent to the 50mol% acidic group), 90 parts of methyl ethyl ketones and 40 parts of Virahols, after at room temperature stirring 3 hours, with collision type decollator Nanomizer (Nanomizer Inc. production), under the pressure of 98Mpa, carry out dispersion treatment, obtain the dispersion liquid of colored reagent.

Then under agitation, with the speed 22 parts of glycerol of dropping of 5ml/min and the mixture of 250 parts of water, obtain the red-purple resin dispersion liquid.From then on remove methyl ethyl ketone and Virahol in the capsule solution with rotatory evaporator, obtain the aqueous dispersions of red-purple resin particle at last.After filtering this aqueous dispersions with the strainer in 1 μ m hole, obtain ink for inkjet recording.

Color resin particulate average particulate diameter in the water quality China ink that obtains like this is 0.12 μ m, this China ink demonstrates the permanent stability of dispersing characteristic aspect and is non-caked, with the operation of Piezo type printing of inkjet printer is stable, the printing thing that this China ink obtains demonstrates clearly red-purple and does not have any diffusion, and all is being outstanding aspect waterproof and the light fastness.

Micro-capsule in the water quality China ink uses super centrifuge separator at acceleration 9.8km/s ²The following precipitation 3 hours of centrifugal condition, coating resin was separated in dry 140 hours with pigment down at 150 ℃ this throw out.The ratio of coating resin and pigment can be used this sedimentary hot analysis to measure, and recording the resin content that is dissolved in the China ink is 0.3% (quality).Preserve after 1 year that this China ink demonstrates the stably stored characteristic and Achromatic color particulate bonding, it all is being outstanding aspect waterproof and the fade resistance energy that the printing thing that obtains with this China ink is at room temperature preserved after 1 year.Embodiment 3 (second example of red-purple China ink)

Get 16 parts of bispins and mediate product, this product contains 8 parts of quinacridones and 40 parts of styrene-propene acid-methacrylic resin (styrene/acrylic/methacrylic acid=77/10/13; Molecular weight=50,000; Acid number=160), add subsequently in the mixing solutions of forming by 46 parts of water, 4 parts of glycerol, 1 part of trolamine (being equivalent to the 50mol% acidic group), 18 parts of methyl ethyl ketones and 8 parts of Virahols, at room temperature stir after 3 hours and under the pressure of 98Mpa, carry out dispersion treatment, obtain dispersing of pigments liquid with collision type decollator Nanomizer (Nanomizer Inc. production).

Under agitation, with the speed 22 parts of glycerol of dropping of 5ml/min and the mixture of 250 parts of water, obtain the carmetta resin dispersion liquid.From then on remove methyl ethyl ketone and Virahol in the capsule solution with rotatory evaporator, obtain the aqueous dispersions of carmetta resin particle at last.

Then, to add in 92 parts of this color resin dispersion liquids as 3 parts of glycerol and 5 parts of propylene glycol propyl ethers of siccative, when stirring, adjust the concentration to 2.7% (quality) of micro-capsule in the dispersion liquid, make it be converted into pigment, obtain ink for inkjet recording after filtering this aqueous dispersions with the strainer in 1 μ m hole.

The average particulate diameter of the micro-capsule in the water quality China ink that obtains like this is 0.15 μ m, and the pH value of China ink is 8.4.Micro-capsule in the water quality China ink uses super centrifuge separator at acceleration 9.8km/s ²The following precipitation 3 hours of centrifugal condition, coating resin was separated in dry 140 hours with pigment down at 150 ℃ this throw out.The ratio of coating resin and pigment can be used this sedimentary hot analysis to measure, and recording the resin Composition that is dissolved in the China ink is 0.4% (quality).

Demonstrate the stable dispersion characteristic in the Mo Yinian that aforesaid method obtains and do not have any bonding.Is stable with Piezo type ink-jet printer with black printing, the printing thing that this China ink obtains demonstrates clearly carmetta, and (gradation of drop-out colour: 1.30), and the printing thing of just having printed soaks in distilled water, and gradation of drop-out colour still demonstrates identical value 1.30 after 24 hours.Embodiment 4 (the 3rd example of red-purple China ink)

The addition polymer of 0.1 part butanols and third rare oxide compound (average mol that third rare oxide compound adds is 17.7) is joined in the China ink that 100 parts of embodiment 3 obtain, and fully stir, so make China ink.

The average particulate diameter of micro-capsule is 0.15 μ m in this China ink, and the pH value is 8.4.When using the step identical with embodiment 3 to measure, the coating resin content that is dissolved in the China ink is 0.4% (quality).

Preserve that this China ink demonstrates the stable dispersion characteristic and do not have any bonding after 1 year, and guaranteed more stable printing.The printing thing of just having printed is done fasterly than the China ink that embodiment 3 obtains, and almost is instantaneous.The printing thing that obtains with this China ink has the diffusion of appropriateness, and the smoothness of solid printing portion also is outstanding, also demonstrates carmetta (gradation of drop-out colour: 1.30) clearly.The printing thing of just having printed soaks value 1.30 identical when gradation of drop-out colour still keeps with firm the printing after 24 hours in distilled water.Embodiment 5 (the 4th example of red-purple China ink)

1 part of ethylene glycol ether is added in the China ink that 100 parts of embodiment 4 obtain, so make China ink.

The average particulate diameter of micro-capsule is 0.15 μ m in this China ink, and the pH value is 8.4.When using the step identical with embodiment 3 to measure, the coating resin content that is dissolved in the China ink is 0.6% (quality).

Preserve that this China ink demonstrates the stable dispersion characteristic and do not have any bonding after 1 year, more stable with this black printing than the printing of the China ink of embodiment 4.The printing thing moment that obtains with this China ink is just dry, and is faster than embodiment 3 and embodiment 4.

The printing thing that obtains with this China ink has appropriate diffusion, and the smoothness of solid printing portion also is outstanding, (gradation of drop-out colour: 1.35), the printing thing of just having printed soaks in distilled water that gradation of drop-out colour is still 1.35 after 24 hours, does not demonstrate any variation also to demonstrate clearly carmetta.Embodiment 6 (example of cyan ink)

The pigment prepared aqueous dispersions that replaces embodiment 3 with C.I.Pigment Blue15:4.

To add in 100 parts of above-mentioned aqueous dispersions as 3 parts of glycerol of siccative with as 5 parts of propyl alcohol of permeate agent, and the content to 2.5% (quality) of adjusting micro-capsule makes it be converted into pigment.After stirring and strainer filtration, obtain ink for inkjet recording with 1 μ m.

The average particulate diameter of micro-capsule is 0.17 μ m in this China ink, and the pH value is 8.6.When using the step identical with embodiment 3 to measure, the coating resin content that is dissolved in the China ink is 0.2% (quality).

After at room temperature preserving 1 year, this China ink still demonstrates highly stable dispersing characteristic, and the stable printing when should China ink having guaranteed to print operation with Piezo type ink-jet printer, printing thing demonstrates clearly cyan (gradation of drop-out colour: 1.30), and the printing thing of just having printed soaks in distilled water, and gradation of drop-out colour still keeps and the firm identical value of having printed 1.30 of printing thing after 24 hours.

Preserve that this China ink demonstrates highly stable dispersiveness and do not have any bonding after 1 year in the Glass Containers at room temperature, and printing is highly stable, does not cause blocking.Print thing and all demonstrate color clearly usually, and demonstrate outstanding water resistance.Embodiment 7 (example of yellow ink)

The pigment prepared aqueous dispersions that replaces embodiment 3 with C.I.Pigment Yellow 151.

To add in 92 parts of above-mentioned aqueous dispersions as 3 parts of glycerol of siccative with as 5 parts of propylene glycol propyl ethers of permeate agent, the content to 3.3% (quality) that to adjust micro-capsule when stirring makes it form as pigment, Zhi Bei aqueous dispersions obtains ink for inkjet recording after the strainer with 1 μ m filters like this.

The average particulate diameter of micro-capsule is 0.18 μ m in this China ink, and the pH value is 8.4.When using the step identical with embodiment 3 to measure, the coating resin content that is dissolved in the China ink is 0.5% (quality).

After at room temperature preserving 1 year, this China ink still demonstrates highly stable dispersing characteristic, and the stable printing when should China ink having guaranteed to print operation with Piezo type ink-jet printer, printing thing demonstrates clearly cyan (gradation of drop-out colour: 1.17), and the printing thing of just having printed soaks in distilled water, and gradation of drop-out colour still keeps and the firm identical value of having printed 1.17 of printing thing after 24 hours.

Preserve that this China ink demonstrates highly stable dispersiveness after 1 year in the Glass Containers at room temperature, and should China ink have guaranteed to print stable printing when operating with Piezo type ink-jet printer machine.General printing thing all demonstrates color clearly, and demonstrates outstanding water resistance.Embodiment 8 (example of black ink)

Replace the pigment of embodiment 3 similarly to prepare aqueous dispersions with carbon black.

To add in 92 parts of above-mentioned aqueous dispersions as 3 parts of glycerol of siccative with as 5 parts of propylene glycol propyl ethers of permeate agent, adjust the content to 3.7% (quality) of micro-capsule when stirring, make it be converted into pigment, after the strainer with 1 μ m filters, obtain ink-vapor recording water quality China ink.

The average particulate diameter of micro-capsule is 0.09 μ m in this China ink, and the pH value is 8.5.When using the step identical with embodiment 3 to measure, the coating resin content that is dissolved in the China ink is 0.6% (quality).

After at room temperature preserving 1 year, this China ink still demonstrates highly stable dispersing characteristic, and the stable printing when should China ink having guaranteed to print operation with Piezo type ink-jet printer, print thing and demonstrate clearly almost ater (gradation of drop-out colour: 1.32), and the printing thing of just having printed soaks in distilled water that gradation of drop-out colour increases to 1.35 after 24 hours, and is higher than original content.

Table 1 illustrates the volume mean diameter in the fresh ink among each embodiment, " doing the increment rate of the volume mean diameter of thin color grains in the black redispersion liquid ", and the standard deviation of particle volume mean diameter (sd).

In the various China inks of above-mentioned each example, find, in the fresh ink and the variation of the volume mean diameter of the micro-capsule among the Chen Mo (loading, be sealed in the container and at room temperature preserve the fresh ink in 1 year) minimum, can ignore.

Table 1

Commercial Application

According to the preparation method of color resin particle aqueous dispersion of the present invention, a color resin that obtains The particle diameter of the color resin particle in the aqueous dispersions of grain is thin, and dispersion has Many dispersing characteristics. Like this, when doing ink-jet printer with China ink with this decentralized system, based on this The China ink of aqueous dispersion demonstrates good dispersing characteristic, has guaranteed ink-jet printer the steady of China ink Fixed ejection had not both had stopped nozzles, do not destroy yet its outstanding print performance such as print quality, Water resistance and fade resistance energy.

The water-dispersion type ink-jet printer that contains colored micro-capsule according to gained of the present invention contains limited amount with China ink Be dissolved in the coating resin (less than 25% (quality)) in the China ink, thinner color grains in the dispersion liquid The increment rate of volume mean diameter reduce to below 50%, like this then make this China ink have highly significant Technology efficiency, such as high dispersion stability, stable ejection characteristic, and image is at print media Upper good set characteristic.

Therefore, China ink of the present invention demonstrates outstanding dispersion stabilization and guarantees that ink-jet printer is with black Stable ejection during printing had not both had stopped nozzles, did not destroy the diffusing type of resin-pellet moisture yet The remarkable performance of water quality China ink such as outstanding print performance, outstanding water resistance and fade resistance Energy.

Claims (6)

1 An inkjet printer ink containing an aqueous dispersion of fine colored particles (d), wherein the fine colored particles (d) are formed by coating the fine pigment particles (a) with a carboxyl-containing coating resin (b), in (1) The surface of the fine colored particles (d) has quaternary carboxyl groups, and the particle volume average diameter is less than 0.5 μm. (2) The "increase rate of the volume average diameter of the fine color particles in the dry ink redispersion liquid" is less than 50%. 2. The ink for inkjet printer according to claim 1, wherein the amount of the resin dissolved in the aqueous medium is less than 2% of the weight of the ink. 3. The ink for inkjet printer according to claim 1, wherein the standard deviation of the "frequency distribution of particle diameters of fine color particles in the dry ink redispersion liquid" is less than 0.15. 4. The ink for inkjet printer according to claim 1, wherein the acid value of the coating resin having a carboxyl group is 50 to 180, and all or part of said carboxyl group is converted into a quaternary ammonium salt by an organic amine compound. 5. A method for preparing ink for inkjet printers, comprising the steps of: (1) Evenly mix the following: (i) color compound (V) prepared by mixing and kneading pigment and carboxyl-containing coating resin (b), (ii) an aqueous medium (W) consisting of an organic solvent (e), and (iii) a base; (2) Prepare a dispersion (X) of fine colored particles in an aqueous medium, wherein the fine colored particles are formed by coating the fine pigment particles (a) with a coating resin (b), and the coating resin (b) contains carboxyl groups and its surface contains quaternary carboxyl groups; and, (3) The organic solvent is removed from the dispersion liquid (X). 6 The method of claim 5, wherein the method further comprises the steps By adding a poor solvent for the coating resin to the dispersion (X) of the fine color particles (d), the coating resin dissolved in the aqueous medium of the above dispersion (X) of the fine color particles (d) is deposited on surface of the fine colored particles, and then the above-mentioned organic solvent (e) is removed from the dispersion (X).

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